Enegy Sources Flashcards
Primary energy source
an energy source, such as coal, wind, oil, gas, or water, which is used directly by the consumer.
Expectancy formula
Reserves / production
Secondary energy source
A secondary energy source is an energy source, such as electricity or hydrogen, which has been transformed from a primary energy source before use by the consumer.
Specific energy
Specific energy is how much energy you can get per unit mass from a fuel. It’s units are J kg
Energy density
Energy you can get per unit volume. It’s units are J m-3
Renewable resources
Can be replenished within a human lifetime ( or does not run out )
What is better oil and gas or coal ?
Oil and gas are better because they burn more efficiently and produce less co2 ( howver cola is cheaper and more plentiful )
Efficiency formula
Useful energy output / energy input
Fossil fuels advantages (3)
Readily available, relatively cheaper and not reliant upon the weather
Most common way to generate electricity is
Coal burning power plant
Nuclear fission
Splitting of atoms of a nucleur fuel to release large amounts of heat energy
Main advantage of nucleur power
Radioactive waste is produced. This can be very dangerous and difficult to dispose of
Units for energy
Jpules
Absorption
Energy is absorbed by atoms ( incraeses kinetic energy )
Reflection of energy
Energy is not absorbed but is rather reflected back along its path
Emission
Energy is absorbed and then released again ( given out again ) . When emitted properties fo teh energy would have changed
Degree of change by teh green house effect ( normally )
Makes earths temperatures around 33 degrees higher than it would otherwise be
Some examples of greenhouse gasses ( 5)
Methane, carbon dioxide, nitrous oxide! Water vapor, ozone
Tehrmal radiation includes ?
Infrared waves and visible light
Energy reaches us from teh sun is teh form of ?
Electromagnetic radiation
Why do hot objects seem to glow ?
Warm objects give out infrared radiation. As objects become hotter, so they begin to give out shorter wavelengths such as light. This is why hot objects, such as metals (toaster element/ cooking grills) glow as they continue to heat up.
Hwo is absorption of colors decided
Thermometers are attached to teh rear of metal pleases which are placed at equal distances form teh radiant heater,. Tehrmal energy from teh radiant heater is absorbed by teh two plates , and teh thermometer helps us asses which color is the best abosirber
Absorptivity
Measure of how much of teh radiation is absorbed by teh body
Transmissivity
Measure of how much radiation passes through teh object
Emmisivity
Measure of how much thermal radiation a body emits to its environment
Balck body
Ideal object taht ahs perfect absorption of all radiation taht falls on it
0 reflectivity and transmissivity
Hwo is black body radiation generated
Oscillating le rice charges in Teh atoms of teh body
Albedo
Albedo is the amount of sunlight (solar radiation) reflected by a surface
Albedo formula
Tottal scattered power/total incident value
Solar Irradation
Amount of electromagnetic radiation received from teh sun per unit are ( normally square meter )
Geothermal energy advantages
free, renewable energy source. No real environmental problems.
Geothermal energy disadvantages
cost of drilling down several km to the hot rocks.
Not available everywhere ( very few places )
Where is geothermal energy used
Used where hot rocks lie quite near to the surface. Cold water is pumped in pipes down to the hot rocks, and returns as steam to drive the turbines.
Biofuels advantages
relatively quick and natural sources of energy and are considered to be carbon neutral (do not release additional carbon dioxide into the atmosphere).
Biofuel disadvantages
natural habitats may be cleared to make way for biofuel crops, and some food crops may be lost.
What are biofuels
Biofuels are renewable energy sources. They can be solids (eg. Straw, woodchip), liquids (eg. Ethanol) or gases (eg. Methane biogas from sludge digesters).
How are biofuels used
They are burnt to turn water into steam, which drives the turbine and producing electricity in the generator.
Solar panels advantages
Advantages: nopollution,averyreliable source in sunny countries. Energy is free, and running costs are almost nil.
Solar panels disadvantages
Only heats water in daytime. Not used to produce electricity.
Photovoltaics ( what is it made out of )
The cell is made of crystalline silicon (a semiconductor) doped with phosphorus and boron impurities.
Solar CELLS advantages
nopollution,averyreliable source in sunny countries. Energy is free, and running costs are almost nil. ( main Tempe is extremely low ), long life ( industrial use 25 - 30 years )
Solar cell disadvantages
Devolping technology, very high initial cost, lots of soace needed
Wave power advantages
no pollution, no fuel costs, minimal running costs. Can be very useful on small islands.
Wave power disadvantages
hazard to boats, can be an eyesore, fairly unreliable as waves disappear when the wind drops, initial costs can be very high, environmental impact.
How does wave power work
As waves come in to the shore they provide up and down motion which can be used to directly drive a turbine which is linked to a generator.
The waves force the air through the turbine, causing it to spin.
